Method and apparatus for forming retaining elements

ABSTRACT

A method of forming a retaining device with hooks, wherein: a molding strip is provided that presents an inside face and an outside face, and that has a plurality of cavities, each cavity defining a stem extending from the outside face towards the inside face and including an end forming a head that extends from the stem towards the inside face of the molding strip; the molding strip is positioned on rotary drive means, the inside face of the molding strip being arranged to bear against the drive means; and molding material is dispensed against the outside face of the molding strip.

GENERAL TECHNICAL FIELD

The present disclosure relates to the field of closure systems, and moreparticularly it relates to closure systems with hooks and to associatedmethods and apparatuses for fabricating them.

STATE OF THE PRIOR ART

Conventional methods and apparatus for making closure systems comprisingself-gripping elements such as hooks conventionally use means forextruding plastics material in a continuous profile and then cutting itand deforming it in the longitudinal direction in order to form thehooks.

Those successive steps would require in particular a plurality ofheating and cooling steps during the method, which leads tocomplexification and to a consequent increase in the dimensions of theapparatus needed for manufacturing.

In addition, each cooling step contributes to increasing the occupationtime of the device, which is penalizing. Furthermore, the need to coolthe material between the various steps of the method and thereforebetween the various workstations of the installation leads to theproduction line being slowed down.

In addition, the workstations and cutting steps consequently lead to anincrease in the dimensions of the apparatus, thereby making it verycomplex to install.

Furthermore, the various manufacturing methods are commonly limited interms of the shape of the retaining elements, the shape of the retainingelements for example being determined by structural elements of theapparatus associated therewith that cannot be modified easily by theuser without requiring consequent modification of the apparatus.

The present disclosure thus seeks to address these various problems.

SUMMARY OF THE DISCLOSURE First Aspect of the Disclosure

In a first aspect, the present disclosure relates to a retaining devicecomprising:

-   -   a base extending in a longitudinal direction and presenting a        top face and a bottom face;    -   a plurality of retaining elements extending from the top face of        the base, each of the retaining elements being formed by a stem        surmounted by a head, the stem having a bottom end connected to        the base, and a top end opposite from the bottom end, the head        surmounting the top end of the stem, and having a bottom face        facing towards the base and a top face opposite from the bottom        face;

the device being characterized in that

-   -   the base presents a thickness lying in the range 10 micrometers        (μm) to 700 μm, where the thickness is the distance between the        top face and the bottom face; and    -   the top face of the head of each retaining element includes a        rib.

In an example, the head of each retaining element includes a catchportion extending radially relative to the top end of the stem, said ribextending at least in part over the catch portion.

In an example, the head of each retaining element includes two catchportions extending radially relative to the top end of the stem, each ofsaid catch portions including a rib, said catch portions extending oneither side of the stem.

The head may then include a rib extending continuously between the twocatch portions.

In an example, the head further includes a transverse rib extendingbetween two opposite ends of the head on either side of an axisextending in the longitudinal direction and passing via the stem and/orthe head, typically via the middle of the stem and/or of the head, thetransverse rib extending over the top end of the stem.

In an example, the at least one catch portion includes a downwardlysloping free end.

In an example, the top face of the head of each retaining element as twodistinct rims extending at least in part over the same catch portion.

In an example, for each retaining element, each of the ribs extends overa fraction only of the periphery of the head, in particular the combinedlength of the ribs of a retaining element under consideration lies inthe range 5% to 95% of the length of the periphery of the head of theretaining element under consideration, more particularly in the range30% to 85% of the length of the periphery of the head of the retainingelement under consideration.

In an example, said base has two edges in the longitudinal direction,and wherein each of said edges presents highs and lows, the maximumoffset between the highs and the lows along a direction transverse tothe longitudinal direction being less than 1 millimeter (mm) over alength in the longitudinal direction that corresponds to threeconsecutive highs.

In an example, the width of the base lies in the range 1 mm to 500 mm,more particularly in the range 3 mm to 100 mm.

In an example, the retaining elements have a height lying in the range 5μm to 5000 μm, or indeed in the range 5 μm to 2000 μm, or moreparticularly in the range 20 μm to 800 μm, with height being measured ina direction perpendicular to the top face of the base.

In an example, the stem of each retaining element presents symmetry ofrotation about an axis perpendicular to the top face of the base.

In an example, each rib of the head extends in a direction that issubstantially transverse (i.e. to within ±30°) to said longitudinaldirection of the base.

In an example, the retaining elements present a shape that isasymmetrical relative to a plane that is transverse to the longitudinaldirection of the base.

In an example, each retaining element presents symmetry relative to aplane extending in a longitudinal direction of the base and containingthe axis of the stem of the retaining element. This rib is arranged insuch a manner as to reinforce of the head of the hook, in particular itscatch portions, in order to facilitate inserting and/or passing fibersor filaments under the head so as to enable them to be retained. Theheight of the rib (measured along a direction perpendicular to the planeof the base) lies typically in the range 0.005 mm to 0.1 mm, preferablyin the range 0.01 mm to 0.08 mm. The term “rib” designates alongitudinal portion that extends, in its height direction, from thesurface of the head substantially away from the base. This represents alength (measured substantially along the longitudinal direction) that isgreater than its width (measured substantially along a transversedirection). More particularly, the ratio of the width over the length ofthe rib is strictly less than 1. In other words, the rib forms aprojection from the top surface of the hook in such a manner that thetop surface of the hook is not flat.

In an example, each catch portion extends in a direction that issubstantially perpendicular to the longitudinal direction of the base.

In an example, each rib, seen from above the hook, presents a V-shape inwhich the angle between the two branches of the upside down V-shape (orU-shape or C-shape) lies in the range 90° to 180°, more particularly inthe range 110° to 170°, or more precisely in the range 140° to 150°. Thetip of the upside down V-shape is typically situated towards the frontof the hook in the longitudinal direction.

In an example, the length of at least one rib in a direction transverseto the longitudinal direction of the base is greater than the diameterof the stem in a direction perpendicular to the longitudinal directionof the base.

Second Aspect of the Disclosure

In a second aspect, the present disclosure relates to a retaining devicewith hooks comprising

-   -   a base extending in a longitudinal direction and presenting a        top face and a bottom face;    -   a plurality of retaining elements extending from the top face of        the base, each retaining element being formed by a stem and a        head;

the device being characterized in that:

-   -   the base presents a thickness lying in the range 10 μm to 700        μm, where the thickness is the distance between the top face and        the bottom face; and    -   the base has two edges in the longitudinal direction, each of        said edges presents highs and lows, wherein the maximum offset        between the highs and the lows along a direction transverse to        the longitudinal direction is less than 1.0 mm over a length in        the longitudinal direction that corresponds to three consecutive        highs.

In an example, in section view on a direction transverse to thelongitudinal direction, said edges present portions of rounded shape.

In an example, the maximum offset between the highs and the lows in adirection transverse to the longitudinal direction and over a length inthe longitudinal direction corresponding to three successive highs, saidmaximum offset lies in the range 0.001 mm to 1.0 mm, more particularlythe range 0.001 mm to 0.5 mm, still more particularly in the range 0.001mm to 0.1 mm.

In an example, the three consecutive highs are over a distance that isless than the distance corresponding to 15 times the hook pitch,preferably less than a distance of 25.0 mm.

In an example, the width of the base measured in a direction transverseto the longitudinal direction lies in the range 1 mm to 500 mm, moreparticularly in the range 3 mm to 100 mm.

In an example, the retaining elements have a height lying in the range 5μm to 5000 μm, or indeed in the range 5 μm to 2000 μm, or moreparticularly in the range 20 μm to 800 μm, or still more particularly inthe range 100 μm to 500 μm, with height being measured in a directionperpendicular to the top face of the base.

In an example, the stem of each retaining element presents symmetry ofrotation about an axis perpendicular to the top face of the base.

In an example, each of the retaining elements is formed by a stemsurmounted by a head, the stem having a bottom end connected to thebase, and a top end opposite from the bottom end, the head surmountingthe top end of the stem, and having a bottom face facing towards thebase and a top face opposite from the bottom face, and wherein the topface of the head of each retaining element includes a rib.

In an example, the retaining elements present a shape that isasymmetrical relative to a direction that is transverse to thelongitudinal direction of the base.

In an example, each retaining element presents symmetry relative to aplane extending in a longitudinal direction of the base and containingthe axis of the stem of the retaining element. The base of the tape isthus free from any extra thickness extending continuously along itsedges, and typically presents a thickness that is substantially constantfrom one edge to the other. A thickness is said to be “substantially”constant when that thickness presents variation of less than 15%. Moregenerally, it can be understood that the base of the tape may be freefrom any non-functional extra thickness (or from any extra thicknesshaving the sole function of improving the regularity of the margins ofthe tape), which is advantageous in production terms in so far as extrathickness leads to overconsumption of material and increases the lengthof time the molds are occupied.

In an example, the device further comprises a layer of nonwoven materialsecured to the bottom face of the base and/or to the top face of thebase, and wherein fractions of fibers and/or filaments of the layer ofnonwoven material are encapsulated in the base.

In an example, the device further comprises a plastics film or anelastic film or a composite film secured to the bottom face of the base,the surface area of the film in contact with the bottom face of the basebeing greater than the projection of the surface area of the film onto aplane defined by the bottom face of the base.

Third Aspect of the Disclosure

In a third aspect, the present disclosure relates to a method ofassembling an assembly comprising a tape of retaining elements and asubstrate, said method comprising the following steps:

-   -   a step of forming a tape of retaining elements by dispensing a        molding material into a molding device, so as to form a tape of        retaining elements comprising a base presenting a bottom face        and a top face, the top face of the base being provided with        retaining elements; and    -   a step of applying a substrate against the bottom face of the        base prior to said bottom face of the base solidifying in such a        manner as to cause the substrate to penetrate at least in part        beyond a plane defined by the bottom face of the base of the        tape.

In an example, during the step of applying a substrate against thebottom face of the base, the bottom face of the base, upstream from theapplication step, is at a temperature that is lower than its meltingtemperature, or more particularly lower than the heat deflectiontemperature of the material forming the base, and the temperature of thebase results solely from the step of forming the tape.

In an example, during the step of applying the substrate against thebottom face of the base, the base is at a surface temperature lyingbetween the melting temperature of the material constituting the baseand the Vicat B softening temperature of the material constituting thebase minus 30° C., more particularly between the melting temperature ofthe material constituting the base and the Vicat A softening temperatureof the material constituting the base, or indeed in the range 75° C. to150° C., in particular substantially equal to 105° C. for a base made ofpolypropylene.

In an example, during the step of applying the substrate against thebottom face of the base, pressure is applied by means of a roller.

In an example, the method includes a subsequent step of unmolding theassembly formed by the tape of retaining elements and the substrate.

In an example, the substrate is a layer of nonwoven material, andwherein portions of fibers and/or filaments of the layer of nonwovenmaterial are encapsulated in the base.

The step of applying the substrate against the bottom face of the baseprior to solidification of said bottom face of the base is thentypically performed in such a manner as to cause portions of fibersand/or filaments of the nonwoven layer to penetrate into the base, atleast in part.

In a variant, the substrate is a plastics film, an elastic film, or acomposite film.

The step of applying the substrate against the bottom face of the baseprior to solidification of said bottom face of the base is thentypically performed in such a manner that the surface area of thesubstrate in contact with the bottom face of the base is greater thanthe surface area of the substrate projected onto the bottom face of thebase, in particular once the base has cooled.

In an example, following the step of applying the substrate, the baseand the hooks are cooled in such a manner as to cause the materialforming the base to shrink, thereby causing local deformation of thebottom face of the base, this deformation giving rise to deformation ofthe top face of the substrate secured thereto.

In another variant, the substrate is a set of thermally-consolidatedfibers and/or filaments.

In an example, the substrate is applied in non-uniform manner againstthe bottom face of the base so as to obtain non-uniform bonding betweenthe base and the substrate.

In an example, the substrate is applied in uniform manner against thebottom face of the base so as to obtain substantially uniform bondingbetween the base and the substrate.

In an example, the step of forming the tape of retaining elements makeselements in relief projecting from and/or recessed in the bottom face ofthe base and distinct from the retaining elements, and wherein the stepof applying the substrate against the bottom face of the base providesbonding between the substrate and the base via said elements in relief.

In an example, during the step of forming the tape of retainingelements;

-   -   a molding strip is provided that presents an inside face and an        outside face, and that has a plurality of cavities, each cavity        defining a stem extending from the outside face towards the        inside face and including an end forming a head that extends        from the stem towards the inside face of the molding strip;    -   the molding strip is positioned on rotary drive means (e.g.        comprising at least two rollers), the inside face of the molding        strip being arranged to bear against the drive means; and    -   molding material is dispensed against the outside face of the        molding strip via material dispenser means arranged facing the        molding strip in such a manner as to define a gap between the        material dispenser means and the molding strip, the molding        material being dispensed in such a manner as to fill said gap        and the cavities with molding material so as to form a tape        comprising a base of thickness that is defined by the gap, and        first preforms projecting from said base, each comprising a stem        and a head, the first preforms being formed by the plastics        material in the cavities of the molding strip.

In an example, during unmolding, the strip and the first preforms areunmolded in such a manner as to deform the first preforms plastically soas to obtain second preforms of shape that is different from the firstpreforms.

It is then possible, after the unmolding step, to perform a forming stepduring which the unmolded tape is inserted into a forming device so asto modify the shape of the heads of the second preforms by forming.

The step of dispensing the molding material is typically performed insuch a manner as to form a tape extending in a longitudinal directionand comprising a base presenting two edges in the longitudinaldirection, each of the edges presenting highs and lows, wherein themaximum offset between the highs and the lows is less than 1.0 mm over alength in the longitudinal direction corresponding to three consecutivehighs, and wherein the step of applying the substrate against the bottomface of the base conserves this maximum offset in a direction transverseto the longitudinal direction between the highs and lows at less than 1mm over a length in the longitudinal direction corresponding to threeconsecutive highs.

This third aspect also provides apparatus for performing a method asdescribed above;

-   -   a molding device and molding material dispenser means adapted to        form a tape of retaining elements comprising a base presenting a        bottom face and a top face, the top face of the base being        provided with retaining elements; and    -   substrate drive means, adapted to apply the substrate against        the bottom face of the tape of retaining elements downstream        from the molding material dispenser means.

In an example, said drive means comprise at least one roller.

Said roller is typically configured so as to press in non-uniform manneragainst the bottom face of the base so as to provide non-uniform bondingbetween the base and the substrate.

This third aspect also provides a retaining device, comprising aplastics tape extending in the longitudinal direction comprising a basepresenting a bottom face and a top face and including a plurality ofretaining elements extending from said top face, and a substrate securedto the bottom face of the base;

the retaining device being characterized in that the substratepenetrates into the base beyond a mean plane defined by the bottom faceof the base of the tape.

In an example, the substrate is a layer of nonwoven material, andwherein portions of fibers and/or filaments of the layer of nonwovenmaterial are encapsulated in the base.

In a variant, the substrate is a plastics film, an elastic film, or acomposite film, and wherein the surface area of the film in contact withthe bottom face is greater than the surface area of the projection ofthe surface of the film onto a plane defined by the bottom face of thebase.

Fourth Aspect of the Disclosure

In a fourth aspect, the present disclosure provides a method of forminga retaining device with hooks, wherein:

-   -   a molding strip is provided that presents an inside face and an        outside face, and that has a plurality of cavities, each cavity        defining a stem extending from the outside face towards the        inside face and including an end forming a head that extends        from the stem towards the inside face of the molding strip;    -   the molding strip is positioned on rotary drive means comprising        at least two rollers, the inside face of the molding strip being        arranged to bear against the drive means;    -   molding material is dispensed against the outside face of the        molding strip by material dispenser means arranged facing the        molding strip in such a manner as to define a gap between the        material dispenser means and the molding strip, the step of        dispensing the molding material being performed in such a manner        as to fill said gap and the cavities with molding material so as        to form a tape comprising a base of thickness that is defined by        the gap, and first preforms projecting from said base, each        comprising a stem and a head, the first preforms being formed by        the plastics material in the cavities of the molding strip; and    -   the strip and the first preforms are unmolded in such a manner        as to deform the first preforms plastically so as to obtain        second preforms of shape that is different from the first        preforms.

In an example, after the unmolding step, a forming step is performedduring which the unmolded tape is inserted into a forming device so asto modify the shape of the heads of the second preforms by forming.

In an example, the forming device comprises at least two rotaryelements, each of said rotary elements having a speed that is differentfrom the drive speed of the tape.

In an example, the molding material is polypropylene, and wherein duringthe forming step, at least one forming element of the forming device ismaintained at a temperature lying in the range 75° C. to 165° C., inparticular substantially equal to 120° C., or indeed substantially equalto 140° C., or more precisely substantially equal to 150° C.

In an example, the step of unmolding the tape and the first preformsleads to a change in the height of the head and/or of the stem, and/orto a change in the width of the head and/or of the stem.

In an example, the forming device comprises an element at ambienttemperature (or at a non-regulated temperature), and at least oneelement at a temperature that lies strictly between the heat deflectiontemperature (HDT) and the melting temperature of the molding material.

In an example, the forming step produces at least one deformation of aportion of the head of each of the second preforms, said deformationtending, for each preform, to deform one of the ends of the head of thepreform so as to form a rib on the top face of the head of the preform.

In an example, during the step of dispensing the molding material, thegap between the material dispenser means and the molding strip lies inthe range 10 μm to 700 μm, more particularly in the range 10 μm to 500μm, or more precisely in the range 50 μm to 100 μm.

In an example, the step of dispensing the molding material is performedin such a manner that the molding material is dispensed while the insideface of the molding strip is bearing against a molding strip driveroller.

In an example, the step of dispensing the molding material is performedthrough a sheet of nonwoven material arranged on the molding strip, saidsheet of nonwoven material including empty zones allowing the moldingmaterial to pass through.

The molding material is then typically polypropylene or a formulationbased on polypropylene, and the step of dispensing the molding materialis typically performed at a pressure lying in the range 10 bar to 100bar, or indeed in the range 30 bar to 50 bar, and at a temperature lyingin the range 150° C. to 300° C.

The molding strip is then typically driven at a travel speed lying inthe range 1 meter per minute (m/min) to 500 m/min, more particularly inthe range 5 m/min to 250 m/min.

In an example, the unmolding step is performed while the base of thetape is at a temperature lower than the melting temperature of themolding material, or lower than the heat deflection temperature of themolding material.

In an example, the step of dispensing the molding material is performedso as to form a tape extending in a longitudinal direction andcomprising a base presenting two edges in the longitudinal direction,each of the edges presenting highs and lows, wherein the maximum offsetbetween the highs and the lows in a direction transverse to thelongitudinal direction is less than 1.0 mm over a length in thelongitudinal direction corresponding to three consecutive highs.

In an example, prior to the unmolding step, a layer of nonwoven materialis applied against the bottom face of the base before the bottom face ofthe base has solidified so as to cause portions of the fibers and/orfilaments of the layer of nonwoven material to penetrate into the base,at least in part.

During the step of applying the nonwoven material against the bottomface of the base, the layer of nonwoven material is then typically atambient temperature (or at a temperature that is not regulated), and thetemperature of the base is the result only of the step of forming thetape.

During the step of applying the layer of nonwoven material against thebottom face of the base, the bottom face of the base is typically at atemperature lower than its melting temperature.

This fourth aspect also provides apparatus for performing a method asdefined above, and comprising:

-   -   a molding device, comprising a molding strip mounted on rotary        drive means (e.g. comprising at least two rollers), the molding        strip having an inside face and an outside face, the inside face        being mounted to bear against the rollers, the molding strip        having a plurality of cavities, each cavity defining a stem        extending from the outside face towards the inside face, and        including an end forming a head extending from the stem towards        the inside face of the molding strip;    -   material dispenser means arranged facing the molding device, and        configured in such a manner as to dispense molding material at a        point of the molding strip so as to form a tape of preforms        having a base of thickness defined by a gap between the material        dispenser means and the molding strip, and first preforms, each        comprising a stem and a head projecting from said base; and    -   unmolding means configured to unmold the tape of preforms formed        in the molding strip;    -   the molding strip and the unmolding means being configured so        that unmolding the tape of preforms leads to the first preforms        being deformed in such a manner as to form second preforms of a        shape that is different from the first preforms.

In an example, the apparatus further comprises a forming deviceconfigured to modify the heads of the preforms by forming.

In an example, the apparatus further comprises drive means for driving alayer of nonwoven material and adapted to press a nonwoven materialagainst the bottom face of the base of the tape of retaining elementsdownstream from the material dispenser means.

This fourth aspect further provides apparatus for forming a retainingdevice with hooks, the apparatus comprising:

-   -   a molding device, comprising a molding strip mounted on rotary        drive means (e.g. comprising at least two rollers), the molding        strip having an inside face and an outside face, the inside face        being mounted to bear against the rollers, the molding strip        having a plurality of cavities, each cavity defining a stem        extending from the outside face towards the inside face, and        including an end forming a head extending from the stem towards        the inside face of the molding strip;    -   material dispenser means arranged facing the molding device, and        configured in such a manner as to dispense molding material at a        point of the molding strip so as to form a tape of preforms        having a base of thickness defined by the gap, and first        preforms, each comprising a stem and a head projecting from said        base; and    -   unmolding means configured to unmold the tape of preforms formed        in the molding strip;

the molding strip and the unmolding means being configured so thatunmolding the strip of preforms leads to the first preforms beingdeformed in such a manner as to form second preforms of a shape that isdifferent from the first preforms.

In an example, this apparatus further comprises a forming deviceconfigured to modify the heads of the preforms by forming.

In an example, the forming device comprises at least two rotaryelements, one of said rotary elements including heater means ortemperature regulator means configured so as to maintain it at atemperature that lies strictly between the heat deflection temperatureand the melting temperature of the molding material.

In another embodiment, the head may be heated prior to the forming stepso that it is at a temperature lying between the heat deflectiontemperature of the molding material and the melting temperature of themolding material, the forming device including an element operating at atemperature that is less than the heat deflection temperature of themolding material, for example.

In an example, said rotary elements of the forming device haverespective speeds that are different from that of the molding device.

In an example, the forming means are configured so as to form at leastone fold in the head of each preform. More particularly, said at leastone fold tends to fold at least one end of the head of the preformtowards a central portion of the head of the preform.

In an example, the forming device comprises a rotary element configuredin such a manner as to operate at ambient temperature or at anon-regulated temperature, and at least one a rotary element havingheater means adapted so that said at least one rotary element operatesat a temperature that lies strictly between the heat deflectiontemperature and the melting temperature of the molding material.

In an example, the rotary elements of the forming device are configuredso as to be driven in rotation at distinct speeds of rotation, therotary element having the lower temperature having a relative speed thatis different from the rotary element(s) having a higher temperature.

In an example, the cavities of the molding strips extend in a cavitydirection that is substantially perpendicular to the outside face of themolding strip, and each defines a stem and a head, each presentingsymmetry of rotation about said cavity direction, the head having adimension that is greater than the maximum dimension of the stem asmeasured radially relative to the cavity direction.

In an example, the material dispenser means are configured so as todispense the molding material at a point of the molding strip while theinside face of the molding strip is pressing against a roller of therotary drive means.

In an example, the gap between the material dispenser means and themolding strip lies in the range 10 μm to 700 μm, more particularly inthe range 20 μm to 500 μm, or more precisely in the range 50 μm to 100μm.

In an example, the rotary drive means for driving the molding stripcomprise at least two rollers, each having a diameter lying in the range10 times to 10,000 times the thickness of the molding strip, inparticular in the range 50 times to 5000 times the thickness of themolding strip, e.g. in the range 100 mm to 250 mm.

In an example, the apparatus further comprises means for pressing astrip of nonwoven material and/or of woven material and/or of knittedmaterial against the molding strip upstream from the material dispensermeans.

In an example, the cavities in the molding strip are through cavities.

In an example, the apparatus further comprises a scraper device arrangedon the inside face of the molding strip, downstream from the materialdispenser means.

In an example, the molding strip includes an inner strip made of rubberforming its inside face, the ends of the cavities of the molding stripbeing formed in said inner strip made of rubber.

Fifth Aspect of the Disclosure

In a fifth aspect, the present disclosure provides a method of forming aretaining device with hooks, wherein:

-   -   a molding strip is provided that presents an inside face and an        outside face, and that has a plurality of cavities, each cavity        defining a stem extending from the outside face towards the        inside face and including an end forming a head that extends        from the stem towards the inside face of the molding strip;    -   the molding strip is positioned on rotary drive means comprising        at least two rollers, the inside face of the molding strip being        arranged to bear against the drive means;    -   molding material is dispensed against the outside face of the        molding strip by material dispenser means arranged facing the        molding strip in such a manner as to define a gap between the        material dispenser means and the molding strip, the step of        dispensing the molding material being performed in such a manner        as to fill said gap and the cavities with molding material so as        to form a tape comprising a base of thickness that is defined by        the gap, and first preforms projecting from said base each        comprising a stem and a head, the first preforms being formed by        the plastics material in the cavities of the molding strip;    -   the tape and the first preforms are unmolded; and    -   the unmolded tape is inserted in a forming device so as to        modify the shapes of the heads of the preforms by forming.

In an example, during the step of unmolding the tape and the firstpreforms, the first preforms are deformed plastically so as to obtainsecond preforms of shape that is different from the shape of the firstpreforms, said second preforms subsequently being deformed by theforming device.

In an example, the forming device comprises at least two rotaryelements, each of said rotary elements having a speed that is differentrelative to the tape.

In an example, the molding material is polypropylene, and wherein duringthe forming step, at least one forming element of the forming device ismaintained at a temperature lying in the range 75° C. to 165° C., and inparticular close to 120° C.

In an example, the step of unmolding the tape and the first preformsleads to a change in the height of the head and/or of the stem, and/orto a change in the width of the head and/or of the stem.

In an example, the forming device comprises an element at ambienttemperature or at a non-regulated temperature, and at least one elementat a temperature that lies strictly between the heat deflectiontemperature (HDT) and the melting temperature of the molding material.

In an example, the forming step produces at least one deformation of aportion of the head of each of the second preforms, said deformationtending, for each preform, to deform one of the ends of the head of thepreform so as to form a rib on the top face of the head of the preform.

In an example, the step of dispensing the molding material is performedin such a manner that the molding material is dispensed while the insideface of the molding strip is bearing against a molding strip driveroller.

In an example, the step of dispensing the molding material is performedthrough a sheet of nonwoven material arranged on the molding strip, saidsheet of nonwoven material including empty zones allowing the moldingmaterial to pass through.

In an example, during the step of dispensing the molding material, thegap between the material dispenser means and the molding strip lies inthe range 10 μm to 700 μm, more particularly in the range 10 μm to 500μm, or more precisely in the range 50 μm to 100 μm.

The molding material is then typically polypropylene, and the step ofdispensing the molding material is typically performed at a pressurelying in the range 10 bar to 100 bar, or indeed in the range 30 bar to50 bar, and at a temperature lying in the range 150° C. to 300° C.

The molding strip is then typically driven at a travel speed lying inthe range 1 m/min to 500 m/min, more particularly in the range 5 m/minto 250 m/min.

In an example, the unmolding step is performed while the base of thetape is at a temperature lower than the melting temperature of themolding material, or lower than the heat deflection temperature of themolding material.

In an example, the step of dispensing the molding material is performedso as to form a tape extending in a longitudinal direction andcomprising a base presenting two edges in the longitudinal direction,each of the edges presenting highs and lows, wherein the maximum offsetbetween the highs and the lows in a direction transverse to thelongitudinal direction is less than 1.0 mm over a length in thelongitudinal direction corresponding to three consecutive highs.

In an example, prior to the unmolding step, a layer of nonwoven materialis applied against the bottom face of the base before the bottom face ofthe base has solidified so as to cause portions of the fibers and/orfilaments of the layer of nonwoven material to penetrate into the base,at least in part.

In an example, during the step of applying the nonwoven material againstthe bottom face of the base, the layer of nonwoven material is atambient temperature or at a temperature that is not regulated, and thetemperature of the base is the result only of the step of forming thetape.

In an example, during the step of applying the strip of nonwovenmaterial against the bottom face of the base, the bottom face of thebase is at a temperature lower than its melting temperature.

This fifth aspect also provides apparatus for performing a method asdefined above, and comprising:

-   -   a molding device, comprising a molding strip mounted on rotary        drive means e.g. comprising at least two rollers), the molding        strip having an inside face and an outside face, the inside face        being mounted to bear against the rollers, the molding strip        having a plurality of cavities, each cavity defining a stem        extending from the outside face towards the inside face, and        including an end forming a head extending from the stem towards        the inside face of the molding strip;    -   material dispenser means arranged facing the molding device, and        configured in such a manner as to dispense molding material at a        point of the molding strip so as to form a tape of preforms        having a base of thickness defined by the gap, and first        preforms each comprising a stem and a head projecting from said        base;    -   unmolding means configured to unmold the tape of preforms formed        in the molding strip; and    -   a forming device, configured to modify the heads of the preforms        by forming.

In an example, the molding strip and the unmolding means are configuredso that unmolding the strip of preforms leads to the first preformsbeing deformed in such a manner as to form second preforms of a shapethat is different from the first preforms.

In an example, the apparatus further comprises drive means for driving alayer of nonwoven material and adapted to press a nonwoven materialagainst the bottom face of the base of the tape of retaining elementsdownstream from the material dispenser means.

This fifth aspect also provides apparatus for forming a retaining devicewith hooks, the apparatus comprising:

-   -   a molding device, comprising a molding strip mounted on rotary        drive means, e.g. comprising at least two rollers, the molding        strip having an inside face and an outside face, the inside face        being mounted to bear against the rollers, the molding strip        having a plurality of cavities, each cavity defining a stem        extending from the outside face towards the inside face, and        including an end forming a head extending from the stem towards        the inside face of the molding strip;    -   material dispenser means arranged facing the molding device, and        configured in such a manner as to inject molding material at a        point of the molding strip so as to form a tape of preforms        having a base of thickness defined by the gap, and first        preforms each comprising a stem and a head projecting from said        base; and    -   unmolding means configured to unmold the tape of preforms formed        in the molding strip;

the molding strip and the unmolding means being configured so thatunmolding the strip of preforms leads to the first preforms beingdeformed in such a manner as to form second preforms of a shape that isdifferent from the first preforms.

In an example, the apparatus further comprises a forming deviceconfigured to modify the heads of the preforms by forming.

In an example, the forming device comprises at least two rotaryelements, one of said rotary elements including heater means ortemperature regulator means configured so as to maintain it at atemperature that lies strictly between the heat deflection temperatureand the melting temperature of the molding material.

In an example, said rotary elements of the forming device haverespective speeds that are different from that of the molding device.

In an example, the forming means are configured so as to form at leastone fold on the head of each preform, said at least one fold tending tofold at least one end of the head of the preform towards a centralportion of the head of the preform.

In an example, the forming device comprises a rotary element configuredin such a manner as to operate at ambient temperature or at anon-regulated temperature, and at least one rotary element having heatermeans adapted so that said at least one rotary element operates at atemperature that lies strictly between the heat deflection temperatureand the melting temperature of the molding material.

In an example, the rotary elements of the forming device are configuredso as to be driven in rotation at distinct speeds of rotation.

In an example, the cavities of the molding strips extend in a cavitydirection substantially perpendicular to the outside surface of themolding strip, and each defines a stem and a head, each presentingsymmetry of rotation about said cavity direction, the head having adimension that is greater than the maximum dimension of the stem asmeasured radially relative to the cavity direction.

In an example, the material dispenser means are configured so as toinject the molding material at a point of the molding strip while theinside face of the molding strip is pressing against a roller of therotary drive means.

In an example, the gap between the material dispenser means and themolding strip lies in the range 10 μm to 700 μm, more particularly inthe range 20 μm to 500 μm, or more precisely in the range 50 μm to 100μm.

In an example, the rotary drive means for driving the molding stripcomprise at least two rollers, each having a diameter lying in the range10 times to 10,000 times the thickness of the molding strip, inparticular in the range 50 times to 5000 times the thickness of themolding strip, e.g. in the range 100 mm to 250 mm.

In an example, the apparatus further comprises means for pressing astrip of nonwoven material against the molding strip upstream from thematerial dispenser means.

In an example, the cavities in the molding strip are through cavities.

In an example, the apparatus further comprises a scraper device arrangedon the inside face of the molding strip, downstream from the materialdispenser means.

In an example, the molding strip includes an inner strip made of rubberforming its inside face, the ends of the cavities of the molding stripbeing formed in said inner strip made of rubber.

Sixth Aspect of the Disclosure

In a sixth aspect, the present disclosure relates to a retaining devicecomprising

-   -   an elastic film extending in a longitudinal direction;

a plastics tape extending in the longitudinal direction comprising abase presenting a bottom face and a top face and including a pluralityof retaining elements extending from said top face;

the retaining device being characterized in that the film, the base, andthe retaining elements are formed integrally by means of extrusion.

In an example, the film, base, and the retaining elements are formedintegrally by successive and/or simultaneous extrusion operations.

In an example, the transition between the elastic film and the base ofthe tape, beside the top face and/or the bottom face, is continuous.

In an example, the plastics tape and the elastic film form anintermediate layer having a bottom face and a top face, said devicefurther comprising a layer of nonwoven material secured to at least aportion of the bottom face of the intermediate layer.

The securing is then typically performed by partial encapsulation insaid intermediate layer.

The partial encapsulation is typically performed in the elastic film ofthe intermediate layer.

The partial encapsulation is typically performed in the plastics tape ofthe intermediate layer. The partial encapsulation may be performed inthe plastics tape of said intermediate layer and in the elastic film ofsaid intermediate layer.

In an example, the device further comprises a nonwoven layer secured tothe top face of the intermediate layer.

The nonwoven layer is then typically secured to the top face of theintermediate layer by means of adhesive.

In an example, at least one of the bottom face and/or of the top face ofthe intermediate layer presents elements projecting from said face,which projecting elements are distinct from the retaining elements.

The projecting elements are typically in the form of spikes.

In an example, the base of the plastics tape presents a thickness lyingin the range 10 μm to 700 μm, where the thickness is the distancebetween the top face and a bottom face, each of the retaining elementsis constituted by a stem and by a head;

the stem having a bottom end connected to the base, and a top endopposite from the bottom end, the head surmounting the top end of thestem, and having a bottom face facing towards the base and a top faceopposite from the bottom face, and wherein the top face of the head ofeach retaining element includes a rib.

In an example, the nonwoven layer is activated. The nonwoven materialmay be activated prior to lamination or indeed the laminate may beactivated over its entire width.

This sixth aspect also provides a method of forming a retaining devicewith hooks, wherein:

-   -   a plastics material in the molten state is dispensed in a        molding device so as to form a tape having a base and retaining        elements projecting from a face of said base; and    -   an elastic material in the molten state is dispensed;

in such a manner that the plastics tape and the elastic film and theretaining elements are made integrally by extrusion, the tape ofplastics material and the elastic film forming an intermediate layer.

In an example, the elastic film is formed to extend the tape.

In an example, after making the intermediate layer, a step is performedof applying a nonwoven layer against the bottom face of the intermediatelayer before said bottom face of the intermediate layer solidifies, insuch a manner as to cause portions of fibers and/or filaments of thenonwoven layer to penetrate at least in part into the intermediatelayer.

During the step of applying the nonwoven layer against the bottom faceof the intermediate layer, the layer of nonwoven material is typicallyat ambient temperature or at a non-regulated temperature, and thetemperature of the bottom face of the intermediate layer is the resultsolely of the step of making the intermediate layer.

In an example, the method includes the step of applying a layer ofnonwoven material against the top face of the intermediate layer.

The layer of nonwoven material is then typically bonded to the top faceof the intermediate layer, typically by using an adhesive.

In an example, prior to forming the intermediate layer, a support layeris positioned on at least a portion of the molding device.

In an example, the method includes a prior step of activating thelayer(s) of nonwoven material.

In an example, prior to dispensing material, a molding strip is providedpresenting an inside face and an outside face, and having a plurality ofcavities, each cavity defining a stem extending from the outside facetowards the inside face, and including an end that forms a headextending from the end of the stem towards the inside face of themolding strip, the molding strip is positioned on rotary drive means,e.g. comprising at least two rollers, the inside face of the moldingstrip being arranged to press against the drive means;

-   -   molding material is then dispensed by material dispenser means        arranged facing the molding strip in such a manner as to define        a gap between the material dispenser means and the molding        strip, the molding material being dispensed in such a manner as        to fill said gap and the cavities with molding material so as to        form a tape comprising a base of thickness that is defined by        the gap, and first preforms projecting from said base, each        comprising a stem and a head, the first preforms being formed by        the plastics material in the cavities of the molding strip; and

wherein the dispensing of material is followed by an unmolding step inwhich the tape and the first preforms are unmolded in such a manner asto deform the first preforms plastically so as to obtain second preformsof shape that is different from the shape of the first preforms.

After the unmolding step, a forming step is typically performed duringwhich the unmolded tape is inserted into a forming device so as tomodify the shape of the heads of the second preforms by forming.

SUMMARY OF THE FIGURES

Other characteristics, objects, and advantages of the present disclosureappear from the following description, which is purely illustrative andnon-limiting, and which should be read with reference to theaccompanying drawings, in which:

FIG. 1 is a diagram showing an example of apparatus for making aretaining device with hooks;

FIGS. 2 to 10 are detail views of the shapes of the resulting retainingelements or preforms;

FIG. 11 reproduces the apparatus shown in FIG. 1, and adds thereto meansfor shaping the resulting preforms;

FIGS. 12A to 12E and 13A to 13J are detail views showing the steps ofshaping the hooks and the shapes of the resulting hooks or preforms;

FIG. 14 is a plan view of the tape obtained in this way, showing theproperties of the margins of the tape;

FIGS. 15 and 16 show an example of apparatus for assembling a substrateto a tape, e.g. a tape including a retaining device with hooks;

FIG. 17 is a diagram showing an example of the product obtained usingsuch apparatus; and

FIG. 18 is a diagram showing another example of a product that can beobtained using the above-described apparatuses.

In all of the figures, elements that are in common are identified byidentical numerical references.

DETAILED DESCRIPTION

FIG. 1 is a diagram showing an example of apparatus for making aretaining device with hooks.

The apparatus as shown comprises a molding strip 1 positioned on rotarydrive means 2 comprising in this example two rollers 21 and 22, andmaterial dispenser means 3 adapted to inject molding material, which mayfor example be a plastics material and/or an elastic material.

The unit formed by the molding strip 1 and the rotary drive means 2 thusforms a molding device.

The example shown comprising two rollers 21 and 22 is not limiting, itbeing possible to vary the number and the arrangement of the roller(s),in particular in order to adapt to the length of the molding strip 1 andto the various stations of the apparatus. By way of example, it would bepossible to use three rollers, or indeed only one, such that the moldingstrip is arranged on the periphery of a single roller. In particular,only one of the two rollers need be driven in rotation by motor means,e.g. the roller 21, the other roller 22 being free, i.e. without motormeans, and being driven in rotation by the molding strip, itself drivenby the roller 21.

The molding strip 1 as shown comprises an inside face 11 and an outsideface 12, the inside face 11 being in contact with the rotary drive means2.

The material dispenser means 3 are arranged to inject the moldingmaterial onto the outside face 12 of the molding strip 1.

More precisely, the material dispenser means 3 are arranged facing themolding strip 1, being spaced apart from the molding strip 1 so as todefine a gap e shown in FIG. 1. Reference A identifies the limit of thematerial injected onto the outside face 12 of the molding strip 1,corresponding to the rear face of the material injected onto the moldingstrip 1, where “rear” is taken relative to the travel direction of themolding strip 1.

The molding strip 1 is provided with a plurality of cavities for makingthe hooks of the retaining device with hooks.

Each cavity 13 is formed in such a manner as to define a stem 14extending from the outside face 12 of the molding strip 1 towards itsinside face 11, together with a head 15 extending between the stem 14and the inside face 11 of the molding strip 1.

In the example shown, the heads 15 of the cavities 13 open out into theinside face 11 of the molding strip 1. The cavities 13 are thus throughcavities. Such an embodiment is not limiting, it being equally possiblefor the cavities 13 to be blind cavities, and thus for them not to openout into the inside face 11 of the molding strip 1.

The portions of the cavity 13 that form the stem 14 typically extend ina direction perpendicular to the outside face 12 of the molding strip 1.The portions of the cavities 13 forming the stem 14 are typically shapesof revolution around an axis perpendicular to the outside face 12 of themolding strip 1, or shapes that present a plane of symmetry extending ina direction parallel to the travel direction of the molding strip 1and/or in a direction perpendicular to the travel direction of themolding strip 1.

By way of example, the portions of the cavities 13 forming the stems 14are generally frustoconical or circularly cylindrical in shape about anaxis perpendicular to the outside face 12 of the molding strip 1, andeach of them presents a rounded fillet at the junction with the outsideface 12 of the molding strip 1.

The portions of the cavities 13 forming the heads 15 typically extendradially or transversely relative to an axis perpendicular to theoutside face 12 of the molding strip 1, and they may present symmetry ofrotation about this axis perpendicular to the outside face 12 of themolding strip 1. The portions of the cavities 13 forming the heads 15typically present a shape that is substantially frustoconical orhexahedral.

The portions of the cavities 13 forming the heads 15 may be linear orrounded, e.g. to form portions that are curved towards the inside face11 or towards the outside face 12 of the molding strip 1 extending fromthe portions of the cavities 13 forming the stems 14.

The portions of the cavities 13 forming the heads 15 may present athickness that is constant or varying.

In the example shown in the figures, the portions of the cavities 13forming the head 15 extend radially around the portions of the cavities13 forming the stems 14, and they present the general shape of a disk,as can be seen in particular in FIG. 2, which is described below.

On its inside face 11 or on its outside face 12, the molding strip 1 maypresent particular texturing, such as slots, an array of grooves, or anarray of passages forming vents or spikes, or it may be substantiallysmooth.

The molding strip 1 may be made up by superposing a plurality of strips,and it is thus not necessarily a single piece or made of a singlematerial.

The material dispenser means 3 are typically arranged so as to injectmolding material into the molding strip 1 at a section of the moldingstrip 1 where it bears against a drive roller, specifically the driveroller 21 in the example shown in FIG. 1. The drive roller then forms abottom for the cavities 13.

When the molding material is injected while the molding strip 1 is notbearing against a drive roller, then the material dispenser means 3 mayinclude a base arranged on the other side of the molding strip 1, sothat the inside face 11 of the molding strip 1 bears against the basewhile material is being injected, the base then forming a bottom for thecavities 13 of the molding strip 1.

The molding strip 1 typically presents a thickness lying in the range 5μm to 5000 μm, or indeed in the range 5 μm to 2000 μm, or more preciselyin the range 20 μm to 800 μm, or indeed in the range 100 μm to 500 μm.

In the longitudinal direction, the molding strip may present a lengthlying in the range 0.5 meters (m) to 5 m.

In the transverse direction, the molding strip may present a width lyingin the range 5 mm to 3000 mm.

Each of the rollers 21 and 22 typically presents a diameter lying in therange 10 times to 10,000 times the thickness of the molding strip 1, orindeed 50 times to 5000 times the thickness of the molding strip 1, moreprecisely a diameter lying in the range 50 mm to 750 mm, or moreparticularly a diameter lying in the range 100 mm to 300 mm.

When compared with conventional forming means such as rollers in whichthe mold cavities are made directly, the use of a molding strip 1associated with drive means 2 is advantageous for several reasons.

The use of a molding strip is particularly advantageous in terms ofmodularity. Specifically, the molding strip can be removed and replacedeasily relative to the drive means, unlike a solid roller for whichdisassembly and reassembly operations are particularly complex to carryout. Such an advantage can be seen in particular when both rollers 21and 22 are fastened at one end only to a frame, leaving the other endfree for receiving and/or removing the molding strip. It is alsopossible to use guide means for the molding strip in order to facilitateinserting and/or removing it.

Furthermore, a molding strip is much easier to make in comparison withmaking a roller that includes molding cavities. Specifically, suchrollers are typically made by stacking successive slices, thus requiringmultiple machining operations and leading to major constraints bothduring assembly and on each occasion there is a change in thespecification of the hooks, and such rollers present considerableweight, requiring them to be held at both ends, with the consequence ofmaking them more complex to replace.

Furthermore, the use of a molding strip coupled to drive means makes itpossible to make a molding device of considerable length whileconserving fabrication and an installation that are simple, inparticular when one of the rollers is mounted to be movable intranslation so as to modify the offset between the rollers, and thusenable the tension of the molding strip to be adjusted. Conversely,making molding rollers of large diameter is typically complex, and leadsto molding means of very great weight, thus implying that the entireassembly needs to be overdimensioned in order to be capable ofsupporting such rollers. Furthermore, making such molding rollers oflarge diameter does not make it possible to obtain acceptabledimensional tolerances.

The various steps in forming a retaining device with hooks by means ofthis apparatus are described below with reference to FIGS. 1 to 4.

FIG. 2 shows the molding material once it has been injected into themolding strip 1. FIG. 2 is a side view (in section) showing the materialin the cavities 13 of the molding strip 1.

As can be seen in FIG. 2, the molding material penetrates into themolding strip so as to fill each cavity 13, thereby forming a stem andhead blank for each of the hooks.

A layer of molding material is also deposited on the outside face 12 ofthe molding strip 1 so as to form a base for the retaining device, thethickness of this layer of molding material being determined by the gape between the material dispenser means 3 and the molding strip 1.

The gap e typically presents a thickness lying in the range 10 μm to 700μm, or typically in the range 10 μm to 500 μm, or indeed in the range 20μm to 100 μm.

In the example shown, the cavities 13 in the molding strip 1 are throughcavities. The apparatus may then include an element such as a scraper 4positioned to scrape the inside face 11 of the molding strip 1 in orderto remove excess molding material, as required. The term “injection” isused to designate the action of shaping a molding material by themelting technique, e.g. dispensing, delivering, molding, injecting,extruding.

Injecting molding material into the molding strip 1 by using thematerial dispenser means 3 thus makes it possible to form a base 51 anda plurality of elements or preforms, each comprising a stem 52 and ahead 53, the assembly thus forming a tape 100. As described below, theelements comprising the stems 52 and the heads 53 are typically firstpreforms that are subsequently subjected to a shaping step in order tomake hooks.

A longitudinal direction is defined relative to the travel direction ofthe tape 100, this longitudinal direction being parallel to the traveldirection of the tape 100. This longitudinal direction is commonlyreferred to as the “machine direction” or “MD”. The longitudinaldirection is designated by the axis MD in the figures.

A transverse direction is also defined, commonly referred to as the“cross direction” or “CD”, corresponding to a direction perpendicular tothe longitudinal direction, and extending parallel to a plane face ofthe tape 100. The transverse direction is designated by the axis CD inthe figures.

The base 51 presents a top face 511 and a bottom face 512 that aretypically substantially parallel, the top face 511 being the faceprovided with hooks and/or preforms.

The base 51 typically presents a thickness lying in the range 10 μm to700 μm, or typically in the range 20 μm to 500 μm, or indeed in therange 50 μm to 100 μm.

The base 51 typically presents a width lying in the range 1 mm to 3000mm, or more precisely in the range 2 mm to 400 mm, or indeed between 3mm and 100 mm, the width of the base 51 being measured along thedirection that is transverse relative to the longitudinal direction,e.g. along a direction parallel to the outside face 12 of the moldingstrip 1.

FIGS. 3, 4, 5 are three views showing hook preforms as formed in thisway by injecting material into the molding strip 1, respectively in aperspective view, a plan view, and a section view.

It should be understood that these figures show the molding material asit is within the cavities 13, each time shown isolated from the moldingstrip 1 in order to show its shape in detail.

As can be seen in these figures, the hook preforms as formed in thisway, specifically the first preforms, are each in the shape of a stem 52of generally cylindrical or conical shape surmounted by a head 53.

A bottom end 521 of the stem 52 is defined, connecting the stem to thebase 51, and a top end 522 of the stem 52 is defined opposite from thebottom end 521 of the stem 52.

The head 53 extends from the top end 522 of the stem 52.

In the example shown, the head 53 is hexagonal in shape with edgesforming circular arcs. The head 53 thus has a plurality of portionsextending radially from the top end 522 of the stem 52. The head 53, andmore generally the assembly formed by the head 53 and the stem 52, thuspresents symmetry of rotation about an axis passing through the centerof the stem 52 and of the head 53. It is possible to envisage variousother shapes for the head 53; the purpose of the example shown is merelyto illustrate one embodiment. The head 53 may in particular be hexagonalin shape.

The apparatus as described and the associated method make it possible tooperate at high tape formation speeds.

Specifically, conventional production lines for making retaining deviceswith hooks operate at low formation speeds, these low formation speedsbeing compensated by widening the tape that is being formed. This limitin terms of formation speed is the result in particular of the timeneeded for the injected material to solidify.

In contrast, the installation and the method as described make itpossible to form a tape at a high formation speed, e.g. faster than 20m/min, or indeed faster than 40 m/min, 60 m/min, 80 m/min, 100 m/min,120 m/min, or 150 m/min, or indeed in the range 1 m/min to 500 m/min, orindeed in the range 5 m/min to 250 m/min. Specifically, the methoddescribed does not require the material that is injected to form thehooks to be cooled completely, and, moreover, using a molding strip ofsmall thermal inertia, possibly presenting through cavities, makes itpossible to improve considerably the rate at which the tape solidifies.

In an embodiment, the material dispenser means 3 may inject the moldingmaterial through a sheet of nonwoven material arranged on the outsideface 12 of the molding strip 1.

A sheet of nonwoven material is then arranged on the outside face 12 ofthe molding strip 1 upstream from the material dispenser means 3. Thesheet of nonwoven material may present empty zones to facilitate passingthe molding material, and also zones that prevent the molding materialfrom passing.

Such an embodiment thus makes it possible to obtain a tape presenting alayer of nonwoven material on its top face, i.e. its face presenting theretaining elements, i.e. the hooks. Injecting the molding materialdirectly onto the sheet of nonwoven material thus makes it possible toensure strong cohesion of the nonwoven material with the base 51.

Furthermore, by calibrating the distribution of the empty zones thatfacilitate passage of the molding material and of the zones that preventpassage of the molding material, it is possible to define a pattern forthe distribution of the hooks.

The substrate in the calibrated zone typically presents air permeabilitythat is greater than 2000 liters per square meter per second (L/m2/s),more particularly greater than 4000 L/m2/s in the hook-passing zone.This permeability characteristic is either intrinsic to the substrate,or else it is imparted to the substrate by treatment, by drilling, bypunching, by needling, by suction, by embossing, or by some othertechnique. In an example, the substrate may be a nonwoven material, e.g.a printed nonwoven material. By way of example, the permeability of thesubstrate may be measured using the 1995 ISO 9237 standard at a pressureof 200 pascals (Pa) with 20 square centimeters (cm2) circular testpieces.

The weight of the nonwoven material typically lies in the range 2 gramsper square meter (g/m2) to 45 g/m2. When the permeability of thenonwoven material is intrinsic, the permeability may be less than 15,000L/m2/s, or indeed less than 7500 L/m2/s. The nonwoven material used istypically a nonwoven material of thickness lying in the range 0.10 mm to0.8 mm, in particular in the range 0.20 mm to 0.60 mm. By way ofexample, the thickness of the nonwoven material may be measured incompliance with the 1997 standard NF EN ISO 9073-2 using its method Afor normal nonwovens at a pressure of 0.5 kilopascals (kPa) and for aduration of 10 seconds (s).

The nonwoven material may also present weak mechanical strength,locally, or it may be mechanically weak intrinsically, such that thenonwoven material is perforated by the molding material when making thehooks or preforms.

The material dispenser means 3 may be adapted to dispense two distinctmaterials simultaneously or successively, thus making it possible todefine two zones made of two distinct materials in the tape 100.

More precisely, the material dispenser means 3 may be adapted to injectsimultaneously a molding material such as polypropylene for forming thebase 51 and the hooks, and an elastic material for forming an elasticmargin extending the base 51.

The molding strip 1 may then present suitable shapes for the variouszones of the tape 100, for example it may present a portion providedwith cavities 13 in order to form preforms or hooks corresponding to theportion where the molding material is injected, and a portion that doesnot present such cavities 13 corresponding to the portion where theelastic material is injected.

FIG. 6 is a diagram showing the unmolding of the previously-formed tape100.

Because of the shape of the cavities, it can be understood that theheads 53 are necessarily deformed in order to enable them to beextracted from the molding strip 1.

The portions of the cavities 13 forming the stems 14 and the heads 15are thus of dimensions suitable for allowing the heads 53 to passthrough the portions of the cavities 13 that form the stems 14 in orderto make unmolding possible.

Unmolding thus leads to the heads 53 being deformed, as showndiagrammatically in FIG. 6. This deformation may be of an elastic and/orplastic nature, and can thus lead to a modification of the heads 53 andof the stem 52 when the deformation is plastic, or the heads 53 and thestems 52 may return to their initial shape after unmolding when thedeformation is elastic.

The nature of the deformation depends particularly on the material used,and also on the shapes of the heads 53 and of the stems 52.

In order to reduce the force exerted on the preforms during unmolding,unmolding is typically performed in a zone where the molding strip isnot in contact with one of the rollers 21 and 22.

In the example shown in FIG. 6, deformation of the head 53 is showndiagrammatically as going from a generally plane shape towards the shapeof a corolla of a flower, with the portions that extend radially ortransversely from the top end 522 of the stem 52 thus going from asubstantially plane configuration to a configuration in which they slopeaway from the base 51. The perimeter of the free end of the head 53typically remains unchanged.

Thereafter, FIGS. 7 to 10 show a portion of the tape 100 as unmolded inthis way.

In the example shown, unmolding the tape 100 has caused the head 53 tobe deformed plastically so that its shape has been modified comparedwith the shape of the portion of the cavity 13 in which the head 15 wasformed.

FIG. 7 is a perspective view of a tape portion 100 as unmolded in thisway, FIG. 8 is a plan view, and FIGS. 9 and 10 are two section views ontwo mutually perpendicular planes identified in FIG. 7.

As can be seen in the figures, and in particular in FIGS. 7, 8, 9, and10, the head 53 is asymmetrical in shape after unmolding; specificallythe direction in which force is oriented during unmolding gives rise todistinct deformations in different portions of the head 53. As shown inFIG. 10, in this example, the portion of the head 53 that is positionedat the front of the preform (where “front” is taken relative to thetravel direction of the molding strip 1) is raised to a greater extentthan the portion of the head 53 that is positioned at the rear of thepreform (where “rear” is taken relative to the travel direction of themolding strip 1), i.e. the portion of the head 53 that is positioned atthe front of the preform has an angle of inclination that has beenmodified more than the angle by which the angle of inclination of theportion of the head 53 that is positioned at the rear of the preform hasbeen modified. Such an embodiment is not limiting, it being possible forthe head 53 to be made in such a manner as to present a shape that issymmetrical after unmolding. This deformation of the head 53 leads tothe formation of a flared collar around a central portion of the head53. This collar presents thickness variations, e.g. a thickness thattapers going away from the stem 52. Relative to the stem 52, the distalend of the collar presents a thickness that is less than the proximalend of the collar. The thickness variations make the mechanical actionof folding easier and reduce the thermal inertia needed for deformationin a subsequent step, e.g. when folding and/or forming in the mannerdescribed below.

More particularly, at least a portion of the collar as formed in thisway presents, in section view, an angle A of at least 15° between themean axis of the portion under consideration of said collar and a planeparallel to the plane of the base 51. More particularly, this angle isgreater than 35°, still more particularly greater than 45°. In FIG. 9,the angle A as shown is substantially equal to 55°, and in FIG. 10, theangle A is substantially equal to 80°.

As a result of forming the collar, the maximum dimension of the head ofthe first preform as measured in a plane parallel to the plane of thebase 51 (and referred to as the width of the head) is reduced by 10% to150%, or indeed by 25% to 100% relative to the width of the head of thesecond preform and/or the diameter of the stem of the second preform.

The height of the head of the second preform is increased by 5% to 100%,or indeed by 12% to 50% relative to the height of the first preform,where height is measured along a plane perpendicular to the plane of thebase 51.

In an example, the width of the head is decreased by 0.05 mm to 0.2 mmfor a stem diameter of about 0.2 mm, where the stem diameters of thefirst and second preforms are substantially identical. The height of thehead is increased by 0.025 mm to 0.1 mm for a stem diameter of about 0.2mm, where the stem diameters of the first and second preforms aresubstantially identical.

It is thus considered that the step of injecting molding material intothe molding strip 1 forms “first” preforms for the hooks, eachcomprising a stem 52 and a head 53 (e.g. as shown in FIGS. 2 to 5), andthat the first preforms are subsequently deformed plastically duringunmolding so as to form “second” preforms of shape that is differentfrom the shape of the first preforms, e.g. as shown in FIGS. 6 to 10.The term “plastic” is used of the deformation to specify that thereremains residual or remnant deformation after elongation and release.

In the example shown in FIGS. 1, 11, and 15, unmolding is performed bymeans of an unmolding roller 6, typically configured in such a manner asto separate the base 51 of the tape 100 from the molding strip 1 underthe effect of tension in the tape and its change of direction. Theunmolding roller may be fitted with suction means and/or a surfacehaving a high coefficient of friction, such as for example a rubbercoating so as to improve grip and limit slip. The unmolding roller maybe motordriven and present a tangential speed that is slightly fasterthan the speed of the strip. The separation between the tape 100 and themolding strip 1 is referenced C in the figures, this point correspondingto the level from which the base 51 of the strip 100 is no longer incontact with the molding strip 1, for example. Provision may be made forthe molding strip 1 to bear against the unmolding roller 6, i.e. theunmolding roller 6 forms a lever in the molding strip 1 to facilitateunmolding the preforms and/or hooks.

The first or second preforms can then be adapted to perform the functionof retaining means, or conversely not to present such properties.

Unmolding is typically performed when the base 51 of the tape 100 is ata temperature lower than the melting temperature of the moldingmaterial, or than the temperature at which the molding material bendsunder load, e.g. when the inside face 11 of the molding strip 1 is at atemperature of about 45° C. and the top face 511 of the base 51 is at atemperature of about 75° C. The temperature of bending under load iscommonly referred to as the “heat deflection temperature” (HDT).

The unmolding step may be followed by a forming step in which the secondpreforms are modified, and in particular their heads 53 are modified.

FIG. 11 is a diagram showing apparatus for performing such a formingstep, and FIGS. 12 and 13 show two successive changes in shape that maybe implemented during such a forming step.

The apparatus shown in FIG. 11 is similar to the apparatus shown in FIG.1, but it also includes a forming device 7 positioned downstream fromthe unmolding roller 6.

The forming device 7 as shown comprises a drive roller 71 and twoforming rollers 72 and 73.

The function of the drive roller 71 is to guide and drive the tape 100.The function of the forming rollers 72 and 73 is to perform a formingaction on the stems 52 and/or on the heads 53 of the preforms obtainedby unmolding.

In the example shown, the forming device 7 comprises two forming rollers72 and 73 serving to perform two successive forming steps that aredescribed below. The forming device 7 is not limited to such anembodiment, and may have some other number of rollers, or more generallyof forming means, in order to perform the desired forming steps. By wayof example, the forming device 7 may be configured so as to perform asingle deformation only, in which case it would have only one formingroller.

The forming rollers 72 and 73 are configured to exert mechanical and/orthermal force on the heads 53 and on the stems 52 of the preforms, so asto give rise to plastic deformation in order to confer a final shape tothe hooks.

There follows a description of an example of forming, given withreference to FIGS. 12 to 16.

After unmolding, the tape 100 is driven by the drive roller 71 of theforming device 7. The forming rollers 72 and 73 are arranged so thateach of them defines a passage between the forming roller in questionand the drive roller 71 through which the tape 100 can pass.

These passages between the drive roller 71 and the forming rollers 72and 73 are dimensioned so as to be smaller than the height of the tape100, or where appropriate, than the height of the tape 100 and of thesubstrate, so that the forming rollers 72 and 73 exert a force on thepreforms.

In the example shown, the two forming rollers 72 and 73 serve to performtwo successive deformation steps on the preforms.

Each of the forming rollers 72 and 73 is driven in rotation at a speedof rotation that is distinct from the speed of rotation of the driveroller 71, and thus also distinct from the travel speed of the tape 100.

Taking the speed of the drive roller 71 as a reference speed, the firstforming roller 72 possesses a tangential speed that is less than that ofthe drive roller 71, e.g. in the range 5% to 200% less than the speed ofthe drive roller 71, or indeed in the range 10% to 80% less than thespeed of the drive roller 71, and the second forming roller 73 typicallypossesses a tangential speed that is greater than that of the driveroller 71, e.g. in the range 5% to 200% greater than that of the driveroller 71, or indeed in the range 10% to 80% greater than that of thedrive roller 71.

Furthermore, each of the forming rollers 72 and 73 is typicallymaintained at a predetermined temperature as a function of the moldingmaterial, e.g. in the range 75° C. to 165° C. or more particularlysubstantially equal to 120° C. for a tape made of polypropylene, whilethe drive roller 71 is maintained at ambient temperature or at atemperature that is not regulated, or at a temperature that is lowerthan the heat deflection temperature, e.g. lower than 65° C.

The drive speed and temperature parameters serve to ensure that theheads 53 of the preforms adhere to and/or rub against and/or slide overthe forming rollers 72 and 73, thereby giving rise to their deformation.

FIGS. 12a to 12e thus show the deformation of a preform after action ofthe first forming roller 72. Arrows illustrate diagrammatically thedirection of rotation of the forming roller 72 and the travel directionof the tape 100.

Upstream from the forming roller 72, the preform under consideration isthe same as that described above with reference to FIGS. 7 to 10.

FIG. 12a is a diagram showing the tape approaching the forming roller72.

Thereafter, FIG. 12b is a diagram showing the forming action of theforming roller 72 on the preform. As can be seen in this figure, theforming roller 72 flattens and deforms a portion of the head 53. Moreprecisely, the forming roller 72 comes into contact with some of thevarious portions of the head 53 that extend from the top end 522 of thestem 52, and takes them towards the central region of the head 53. Thisdeformation of the preform gives rise to partial softening both of theportion that is taken towards a central region of the head 53 and alsoof the material of the central region of the head 53, and it also givesrise to a substantially plane sloping region being formed on one face ofthe head 53.

FIG. 12c is a diagram showing the preform after the action of theforming roller 72. FIGS. 12d and 12e show two other views, respectivelya perspective view and a plan view of such a preform deformed in thisway.

As can be seen in this figure, in this example the forming roller 72 hasdeformed the face of the preform at the front of the preform relative toits travel direction.

This deformation gives rise to a rib being formed that extends in adirection that is substantially transverse relative to the longitudinaldirection of the tape 100.

The deformation action exerted by the forming roller 72 folds over aportion of the head 53 of the preform corresponding to the face of thepreform in the travel direction, however this deformation action leadsto flattening of the portions of the head of the preform 53 extending inthe transverse direction relative to the travel direction, therebyforming fins extending on either side of the stem 52 in the directionextending transversely to the travel direction of the tape 100. Thesefins define catch portions 54 of the head 53, extending radially beyondthe stem 52 of the preform from the top end 522 of the stem 52.

The deformation performed by the forming roller 72 forms a first rib 81extending at least in part over the catch portions 54.

More generally, the deformation performed by the forming roller 72 leadsto a catch portion 54 being formed together with a rib extending atleast in part over the catch portion 54. The rib as formed in this wayextends over the top face of the head 53, thereby providing the head 53with mechanical reinforcement.

When the head 53 has a plurality of catch portions 54, the forming canthen give rise to a single rib being formed that extends continuouslybetween the catch portions 54, or to a plurality of disjoint ribs, eachextending at least in part over one or more of the catch portions 54.

After this first deformation by the forming roller 72, seconddeformation may be performed by the forming roller 73.

FIGS. 13a to 13j are diagrams showing the deformation of the preform bythe forming roller 73, and the shape of the resulting hook. Specificallythe term “hook” is used once the preforms have been subjected to theforming steps.

FIGS. 13a and 13b show the deformation of the preform by the formingroller 73. As can be seen in these figures, the forming roller 73 isconfigured to come into contact with a front portion of the preformrelative to its travel direction, and to deform the head 53 of thepreform.

The temperature and speed of rotation parameters of the forming roller73 give rise to adhesion of the material of the head 53 of the preform,which serves to stand up a portion of the head 53 projecting from thestem 52.

It should be observed in particular that relative to the tape 100, theforming roller 73 has a direction of rotation that is identical to thatof the above-described forming roller 72, and that it possesses atangential speed that is greater than the tangential speed of the driveroller 71.

As a result of these direction and speed of rotation characteristics,the forming roller 73 deforms the head 53 of the preform in such amanner as to entrain the material of the head 53 towards the front ofthe preform (relative to its travel direction).

As a result, the forming roller 72 performs first deformation of thepreform tending to take material from the front of the preform towardsthe central portion of the head 53, whereas the forming roller 73performs second deformation of the preform tending to take materialtowards the front of the preform.

The previously-formed first rib 81 is thus taken back towards the frontof the preform, and it extends beyond the stem 52 of the preform. Thefirst rib as modified in this way is given the reference 81′ in thefigures. For reasons of readability, the text refers throughout to thefirst rib with the reference 81.

A substantially transverse second rib 82 is formed, likewise extendingbetween two transverse ends of the hook, in this example formed by thecatch portions 54.

As can be seen in FIGS. 13c to 13j , the hook as formed in this way hasa first rib 81 that is a result both of the action of the first formingroller 72 and of the action of the second forming roller 73, and also asecond rib 82 that is the result of the action of the second formingroller 73.

Each of these two ribs 81 and 82 extends between two opposite ends ofthe hook in the transverse direction, i.e. between the two catchportions 54 in the example shown.

With reference to the drive direction of the tape through theinstallation, the hooks define a front face and a rear face. The firstrib 81 extends substantially along the front faces of the catch portions54, while the second rib 82 extends substantially along the rear facesof the catch portions 54. The catch portions 54 thus typically comprisetwo distinct ribs extending at least in part over the catch portion inquestion.

The catch portions 54 and the first and second ribs 81 and 82 thusdefine transverse ends of the hooks having the same substantiallyU-shaped shape, with a base that is substantially plane and with the tworibs extending in a direction that is substantially perpendicular.

The ribs 81 and 82 thus provide mechanical reinforcement for the catchportions 54, which portions are configured to cooperate withcomplementary elements such as other hooks or loops in order to form aretaining system. The term “mechanical reinforcement” is used herein tomean that the hook deforms less under the action of a given force whenit has one or more such ribs, than would a similar hook not having sucha rib.

The catch portions 54 may extend substantially radially relative to thestem 51, or they may present a free end that slopes towards the base 51,as can be seen for example in FIG. 13e, 13i , or 13 j, thus making itpossible to improve the retention properties of the hook.

Each rib 81 and/or 82 extends over a fraction only of the head 53. Theribs thus typically extend over only a fraction of the periphery of thehead 53. The combined length of the ribs typically lies in the range 5%to 95% of the length of the periphery of the head 53, or more preciselyin the range 30% to 70% of the length of the periphery of the head 53.The periphery of the head 53 is considered as being the radial peripheryof the head 53 after the step of forming the hooks or while being formedin the molding strip 1.

In this example, at least one of the ribs 81 and 82 typically presents alength that is greater than the diameter of the stem 52, its diameterbeing measured in a direction that is transverse to the longitudinaldirection.

As can be seen in the figures, and more particularly in FIGS. 13d and13h , when seen from above the hook, each of the ribs 81 and 82 presentsa generally upside down V-shape (or U-shape or C-shape) having twobranches forming an angle, which angle typically lies in the range 90°to 180°, or more precisely in the range 110° to 170°, or indeed in therange 140° to 150°, or is substantially equal to 145°. The two branchesof the generally V-shaped rib thus converge towards the front of thehook. This embodiment is purely illustrative, and the generally V-shapedshape may be inverted, such that the rib converges towards the rear ofthe hook, e.g. by modifying the speed parameters of the forming device7. The tip of the upside down V-shape, or where appropriate, of theU-shape or of the C-shape, may point towards the front in thelongitudinal direction.

Typically, the ribs 81 and 82 are symmetrical about a plane extending ina longitudinal direction of the base 51 and containing a central axis ofthe stem 52 of the retaining elements.

The hooks as formed in this way typically have a height lying in therange 5 μm to 5000 μm, or indeed in the range 5 μm to 2000 μm, or moreparticularly in the range 20 μm to 800 μm, or still more particularly inthe range 100 μm to 500 μm, with the height being measured in adirection perpendicular to the top face 511 of the base 51.

The head 53 may be heated prior to the forming step so that it is at atemperature lying between the heat deflection temperature of the moldingmaterial and the melting temperature of the molding material, and theforming device 7 may include a rotary element at a temperature that isless than the heat deflection temperature of the molding material, forexample.

As can be seen in particular in FIGS. 13f, 13g , and 13 j, the hookpresents a substantially plane sloping region on the face of the headthat is arranged at the rear of the hook (relative to the traveldirection of the molding strip 1).

Another aspect of the device as described relates to the regularity ofthe tape produced in this way.

Injecting molding material by using the material dispenser means 3 makesit possible to obtain a tape having edges in the longitudinal directionthat are substantially straight immediately on making the tape, andwithout requiring an additional cutting step.

FIG. 14 is a diagram showing the tape 100 as described above when seenfrom above, which tape comprises a base together with preforms or hooks.In the example shown in FIG. 14, the tape 100 is shown as being providedwith preforms as described above, in particular with reference to FIGS.7 to 10.

This figure is a diagram of the tape 100 obtained as a result ofinjecting material into the molding strip 1, the tape thus extending ina longitudinal direction as identified by an axis X-X in FIG. 14. FIG.14 also shows the transverse direction, identified by an axis Y-Y. Thelongitudinal direction identified by the axis X-X in this example isparallel to the machine direction, i.e. to the direction in which thetape 100 is driven.

Two edges 102 and 104 are defined for this tape 100, each edge extendingalong the longitudinal direction, these two edges 102 and 104 definingthe two ends of the tape 100 in a transverse direction perpendicular tothe longitudinal direction.

The hooks or preforms are generally arranged in the proximity of theedges 102 and 104. The hooks or preforms are typically arranged at adistance D from the edges 102 and 104 lying in the range 2 to 3 timesthe pitch P of the hooks, typically equal to 2 or 3 times the pitch P ofthe hooks, the distance D being measured along the transverse directionrelative to the longitudinal direction represented by the axis X-X inFIG. 14. The pitch P between two hooks corresponds to the distancebetween two successive hooks along the longitudinal direction. In theexample shown in FIG. 14, the hooks or preforms are arranged in columnsextending in the longitudinal direction represented by the axis X-X,these columns being repeated identically in the transverse direction.The hooks or preforms could equally well be arranged in a staggered or“honeycomb” configuration, e.g. by offsetting the columns of hooks orpreforms in the longitudinal direction.

As shown in FIG. 14, each of the edges 102 and 104 presents a successionof highs and lows, said succession extending in the longitudinaldirection, and said highs and lows extending in a plane parallel to theplane formed by the base 51, the highs and lows representing smallirregularities in the distribution of molding material for forming thetape 100, it being understood that an edge that is accuratelyrectilinear cannot be made industrially.

The lows should be understood as regions of the edges 102 and 104 thatare indented towards the inside of the tape 100, while the highs shouldbe understood as being regions of the edges 102 and 104 that bulgetowards the outside of the tape 100.

The regularity of the edges 102 and 104 can thus be evaluated using thesuccessive highs and lows.

In section view on a direction transverse to the longitudinal direction,the edges 102 and 104 present portions of rounded shape. Moreparticularly, the rounded shape is oriented laterally towards theoutside of the base. This rounded shape is made while forming the base.In other words, this rounded shape is not obtained by cutting.

The apparatus and the method as described above make it possible toobtain edges 102 and 104 of the tape such that for a length L along thelongitudinal direction corresponding to three consecutive highs, themaximum offset E between the highs and lows in a direction transverse tothe longitudinal direction is less than 3.0 mm, or more precisely lessthan 2.0 mm, or indeed more precisely less than 1.0 mm, or indeed lyingin the range 0.001 mm to 1.0 mm, more particularly in the range 0.001 mmto 0.5 mm, still more particularly in the range 0.001 mm to 0.1 mm.

Such a definition is equally applicable to a length corresponding tothree consecutive lows; the maximum offset between the highs and lows ina direction transverse to the longitudinal direction is less than 3.0mm, or more precisely less than 2.0 mm, or indeed more precisely lessthan 1.0 mm, or indeed lies in the range 0.001 mm to 1.0 mm, moreparticularly in the range 0.001 mm to 0.5 mm, still more particularly inthe range 0.001 mm to 0.1 mm.

The three consecutive highs or lows lie typically over a distance thatis less than the distance corresponding to 15 times the hook pitch,preferably less than a distance of 25 mm.

Obtaining edges 102 and 104 that can thus be said to be “straight” isadvantageous in that it makes it possible to avoid a subsequent step ofstraightening the edges, e.g. by using a cutting step, where suchstraight edges are perceived by the user as being a sign that theproduct is of good quality.

Furthermore, the apparatus and the method used make it possible toobtain such edges that are straight without requiring any longitudinalextra thicknesses in the margins of the tape, where such extrathicknesses do not present any functional advantage. The base 51 of thetape 100 may thus be free from any extra thickness extendingcontinuously along its edges, and typically presents a thickness that issubstantially constant from one edge to the other. More generally, itcan be understood that the base 51 of the tape may be free from anynon-functional extra thickness (where the only function would be toimprove the regularity of the margins of the tape), which isadvantageous in production terms in so far as extra thicknesses wouldlead to overconsumption of material and would increase the length oftime the molds are occupied.

As can be understood from the above description, the straight edges areobtained by injecting the molding material via the material dispensermeans 3. The subsequent steps of unmolding and of forming conserve thestraight edges as described above, in so far as the steps do not involveapplying forces to the edges of the base 51 of the tape 100. The tape100 as obtained in this way after those various steps thus presents anedge that is straight, as defined above.

Furthermore, when at least two distinct materials are dispensedsimultaneously or successively by the material dispenser means 3, theinterface between the two materials is then typically made so as topresent a straight boundary, as described above with reference to theedges of the base 51 of the tape 100. More precisely, when two materialsare dispensed simultaneously or in succession, each material is injectedby the material dispenser means 3 in such a manner as to form straightedges at both of the transverse ends of the tape of material formed inthis way. Consequently, the junctions between the two materials arejunctions between two straight edges as defined above, and thus each ofthem presents a profile that can be said to be “straight” in accordancewith the above definition. By way of example, the dispenser means maycomprise two injection or extrusion nozzles.

The above described apparatus and the associated method may also presentmeans and a step for associating a substrate with the tape.

Such association of a substrate with a tape having gripper elements istypically performed by means of an adhesive, or by melting the base orthe substrate, as mentioned above.

In order to secure a substrate to the base of the tape, the proposedapparatus may include substrate drive means adapted to feed substrateand to apply the substrate against the bottom face 512 of the base 51 ofthe tape 100 downstream from the material dispenser means 3.

FIGS. 15 and 16 are diagrams showing an example of apparatus includingsuch means.

The apparatus as shown is similar to that described above with referenceto FIG. 1; elements in common are therefore not described again.

As can be seen in FIGS. 15 and 16, the apparatus as described hassubstrate drive means 9, constituted in this example by two rollers 91and 92, which rollers are configured to feed substrate 200 downstreamfrom the material dispenser means 3.

The substrate 200 is typically a layer of nonwoven material, a plasticsfilm, an elastic film, or a composite film, or indeed an assembly ofthermo-consolidated fibers and/or filaments. By way of example thesubstrate 200 is a sheet of fibers and/or filaments.

In the example shown in FIGS. 15 and 16, the substrate is shown as beinga layer of nonwoven material.

The term “nonwoven” material is used to designate a product obtained asa result of forming a sheet of fibers and/or filaments that have beenconsolidated. Consolidation may be mechanical, chemical, or thermal, andit gives rise to bonds being present between the fibers and/or thefilaments. Such consolidation may be direct, i.e. performed directlybetween the fibers and/or the filaments, by welding, or it may beindirect, i.e. via an intermediate layer between the fibers and/or thefilaments, e.g. a layer of adhesive or a layer of binder. The term“nonwoven” material relates to a structure in the form of a tape orsheet of fibers and/or filaments that are interleaved in a manner thatis not uniform, i.e. irregular, or at random. A nonwoven material mayhave a single-layer structure or a structure made up of multiple layers.A nonwoven material may also be combined with some other material inorder to form a laminate. A nonwoven material may be made from varioussynthetic and/or natural materials. By way of example, natural materialscomprise cellulose fibers, such as cotton, jute, flax, and the like, andmay also include cellulose fibers that have been reprocessed, such asrayon or viscose. Natural fibers for a nonwoven material may be preparedby using various methods such as carding. By way of example, syntheticmaterials comprise, but without being limited thereto, syntheticthermoplastic polymers known for forming fibers that include, withoutbeing limited thereto, polyolefins, e.g. polyethylene, polypropylene,polybutylene, or the like; polyamides, e.g. polyamide 6, polyamide 6.6,polyamide 10, polyamide 12, and the like; polyesters, e.g. polyethyleneterephthalates, polybutylene terephthalates, polylactic acids, and thelike, polycarbonates, polystyrenes, thermoplastic elastomers, vinylpolymers, polyurethanes, and mixtures and copolymers thereof. By way ofexample, the nonwoven material may be a material of the type: Spunbond,Spunmelt, melted carded, SMS, SMMS, SS, SSS, SSMMS, SSMMMS, Air through,etc.

The substrate is not limited to a nonwoven material, and could moregenerally be a nonwoven material, a woven material, a knitted material,or a combination of a plurality of these materials.

The substrate drive means 9 are configured to feed the apparatus withsubstrate 200 and to apply the substrate 200 against the bottom face 512of the base 51 of the tape 100 downstream from the material dispensermeans 3.

The substrate drive means 9 are configured in such a manner that thisapplication takes place prior to the base 51 of the tape 100solidifying. Thus, this application causes at least part of thesubstrate 200 to penetrate beyond a plane defined by the bottom face 512of the base 51 of the tape 100. In the figures, reference B designatesthe point where the base 51 of the tape 100 is put into contact with thesubstrate 200.

More precisely, the bottom face 512 of the base 51 is substantiallyplane, and it defines a plane. Applying the substrate against this facecauses portions of the substrate 200, e.g. fibers and/or filaments ofthe layer of nonwoven material when the substrate 200 is a layer ofnonwoven material, to penetrate into the base 51, thus passing throughthe bottom face 512 of the base 51. FIG. 17 is thus a diagram showing anexample of a product that results from this bonding between the tape 100and the substrate 200.

In so far as such application takes place before the base 51 of the tape100 has solidified, there is no need to heat the base 51 of the tape 100and/or the substrate 200 in order to achieve such bonding.

By way of example, assuming that the base 51 is made of polypropylene,the substrate is typically applied against the bottom face 512 of thebase 51 while the bottom face 512 of the base 51 presents a temperaturelying between the melting temperature and the Vicat B softeningtemperature of the material constituting it minus 30° C., or indeedbetween the melting temperature of the material constituting it and theVicat A softening temperature of the material constituting it. Moreparticularly, when the base comprises material based on polypropylene,the bottom face 512 of the base 51 presents a temperature lying in therange 75° C. to 150° C., typically about 105° C., this temperaturetypically being measured by means of an infrared camera or a laser. TheVicat softening temperature is the temperature obtained using one of themethods described in the ISO 306 or the ASTM D 1525 standards whileheating at a rate of 50° C. per hour (° C./h) and with a standardisedload of 50 newtons (N) for Vicat B and a standardised load of 10 N forVicat A.

More generally, while the substrate 200 is being applied against thebottom face 512 of the base 51, the bottom face 512 of the base 51 is ata temperature lower than its melting temperature, or more particularlylower than the heat deflection temperature of the material forming thebase 51, or indeed substantially equal to ambient temperature (or to anon-regulated temperature), and the temperature of the base 51 resultssolely from the step of forming the tape 100. With reference toabove-defined points A, B, and C, and as can be seen in particular inFIG. 15, the distance traveled by the base 51 between the points A and Btypically lies in the range 20.0 mm to 400 mm. Likewise, the distancetraveled by the base 51 between the points B and C typically lies in therange 400 mm to 1500 mm. The distance traveled by the base 51 betweenthe points B and C is typically twice as long as the distance traveledby the base 51 between the points A and B.

The roller 92 is typically configured so as to apply the substrate 200with pressure against the bottom face 512 of the base 51 so as tofacilitate penetration of the substrate 200 to the base 51.

The roller 92 may present patterns or portions in relief on its surface,so as to enhance penetration of the substrate 200 into the base 51.

The substrate 200 may be applied in uniform or non-uniform manneragainst the bottom face 512 of the substrate 51.

The bonding achieved between the substrate 200 and the base 51 of thetape 100 may be uniform or non-uniform.

When the substrate 200 is a set of thermally consolidated fibers and/orfilaments, the bonding with the base 51 is also achieved by a fractionof the fibers and/or filaments of the substrate 200 penetrating into thebase.

When the substrate 200 is a set of thermally consolidated fibers and/orfilaments, a plastics film, an elastic film, or a composite film, aphenomenon might occur during bonding with the base whereby the tape 100shrinks during cooling, this shrinking enhancing the bonding areabetween the substrate and the base of the tape. This shrinking is of noimpact on the visual appearance for the final user.

More precisely, it is well known that molded parts present a shrinkagephenomenon during cooling of the material. In the present example, thetape 100 presents portions of different thicknesses as a result of thepresence of the retaining elements projecting from the top face 511 ofthe base 51. Such zones presenting extra thickness lead to phenomena ofthe material shrinking in register with the stems 52 of the hooks, thusforming zones 530 of material shrinkage in the bottom face 512 of thebase 51.

However, in so far as the substrate 200 is applied against the bottomface 512 of the base 51 prior to solidification of the base 51, thisshrinkage of material takes place after the substrate has been appliedagainst the bottom face 512 of the base 51.

Pressing the substrate 200 against the bottom face 512 of the base 51 inassociation with the fact that the base 51 has not yet solidified duringthis application leads to bonding by molecular diffusion between thesubstrate 200 and against the bottom face 512 of the base 51. Thus,during shrinkage of the material of the base 51 as it solidifies, asmentioned above, the substrate 200 remains in contact with the bottomface 512 of the base 51, and regions of the film forming the substrate200 thus continue to fit closely to the shape of the material shrinkagezones in the bottom face 512 of the base 51. These regions of the filmforming the substrate 200 thus penetrate beyond the plane defined by thebottom face 512 of the base 51. Thus, the surface area of the filmforming the substrate 200 in contact with the bottom face 512 of thebase 51 is greater than the projection of the surface area of the filmonto a plane defined by the bottom face 512 of the base 51, thus makingit possible to increase adhesion between the substrate 200 and the tape100.

When the substrate 200 is a layer of nonwoven material, the hooks areunmolded easily, even with a nonwoven material presenting a weight ofless than 80 g/m2. By way of example, the weight of the nonwovenmaterial may lie in the range 5 g/m2 to 120 g/m2, or indeed in the range10 g/m2 to 70 g/m2.

When the substrate 200 is a layer of nonwoven material, the apparatusmay include a calendering device upstream from the substrate drive means9, thus making it possible (optionally locally) to perform a calenderingstep on the layer of nonwoven material prior to applying it against thetape 100.

This technique for bonding the substrate 200 to a tape 100 isadvantageous, in particular in that it does not lead to the tape 100becoming deformed, and thus advantageously makes it possible to conservethe shape of the base 51 as obtained during the injection step, and inparticular to conserve the straight edges that can be obtained using theabove-described method and apparatus.

This bonding of a substrate to a tape can be applied to a method offorming a tape as described above, or more generally to any other methodof forming a tape that includes retaining elements such as hooks.

The various above-described apparatuses and methods may be usedindependently or in combination.

By way of example, there follows a description with reference to FIG. 18of a product that can be obtained using the above-described apparatusesand methods.

FIG. 18 thus shows a product 300 comprising a tape 100 made out of aplastics material, the tape 100 being formed integrally with a film ofelastic material 310 by extrusion. More particularly, the tape 100 madeof plastics material is formed integrally with an elastic material film310 by extrusion operations that may be simultaneous or in succession.The term “extrusion operations in succession” is used herein to meanthat the film 310 and/or the tape 300 is made continuously with theformation of the tape 300 and/or of the film 310, or indeed on a singleproduction line.

FIG. 18 is a section view on a plane perpendicular to the longitudinaldirection of the product 300 being formed.

The tape 100 is similar to the tape as described above, and it comprisesa base 51 and hooks extending from the top face 511 of the base 51.

The film of elastic material 310 is extruded simultaneously,successively, or prior to extruding the tape 100 by the materialdispenser means 3, thereby defining a bond between the tape 100 and thefilm 310 at one of their transverse ends. The transition between theelastic film 310 and the base 51 of the tank 100 is thus typicallycontinuous.

Thus, the film of elastic material 310, the base, and the retainingelements of the tape 100 made of plastics material are made integrallyand are the result of extrusion.

Numerical reference 320 designates the interface between the film ofelastic material 310 and the tape 100.

The term “integrally” is used to mean that the tape and the film arebonded together solely by simultaneous or successive distributions ofmaterial, e.g. by simultaneous or successive extrusion operations. Inother words, the resulting bonding is achieved solely by intramoleculardiffusion from the tape to the elastic film and/or from the elastic filmto the tape.

This interface 320 may be made in a plane that is substantially parallelto the longitudinal direction of the product 300, as shown in FIG. 18,or it may be made by overlap between the elastic film 310 and the tape100.

When the hooks and the base are made out of the same material, it can beseen that there is continuity of material from the base towards thehooks, and vice versa. In other words, the material forming the hooksand the material forming the base are contiguous.

The elastic film 310 is defined as having a top face 311 and a bottomface 312. In the example shown in the figure, the top face 311 of theelastic film 310 in this example extends the top face 511 of the base 51of the tape 100. In the example shown in FIG. 18, the bottom face 312 ofthe elastic film 310 in this example extends the bottom face 512 of thebase 51 of the tape 100.

The assembly formed by the elastic film 310 and by the tape 100 thusconstitutes an intermediate layer, presenting a bottom face and a topface.

As can be seen in FIG. 18, a substrate 200 is secured to the bottom faceof the intermediate layer, i.e. to the bottom face 312 of the elasticfilm 310 and to the bottom face 512 of the base 51 of the tape 100

The substrate 200 may for example be a nonwoven material, as describedabove.

The substrate 200 is secured to the intermediate layer by partialencapsulation in said intermediate layer, i.e. by partial encapsulationof the substrate in the base 51 of the tape 100 and in the elastic film310. This bonding is performed using the method and the apparatus asdescribed above with reference to FIGS. 15 to 17.

The product 300 as shown also has a support layer 330 secured to the topface of the intermediate layer. This support 330 extends over the topface 311 of the elastic film 310, and also at least in part over the topface 511 of the base 51 of the tape 100.

The support layer 330 may be identical in composition to the substrate200, or it may have a different composition; for example, it may be alayer of nonwoven material, a knit, or a grid.

In the example shown, the support layer 330 is secured on the top faceof the intermediate layer by adhesive. FIG. 18 is thus a diagram showinga layer of adhesive 340 extending over the top face 311 of the elasticfilm 310, and also at least in part over the top face 511 of the base 51of the tape 100.

The support layer 330 is then typically secured to the top face of theintermediate layer after securing the substrate 200 to the bottom faceof the intermediate layer.

It can readily be understood that securing in this way is merelyillustrative, and that any other suitable method may be used forsecuring the support layer 330 on the top face of the intermediatelayer.

By way of example, the support layer 330 may be arranged on the moldingstrip 1 prior to the material dispensing means 3 dispensing material,such that the plastic and elastic material materials are injected ontothe molding strip while the support layer 330 is positioned on themolding strip 1, as mentioned above.

The top face and/or the bottom face of the base 51 of the tape 100and/or of the elastic film 310 may optionally be smooth (with theexception of the hooks). By way of example they may present elements inrelief, e.g. transition elements, hooks that have been eliminated,recesses such as holes or slots, or projections such as spikes, points,domes, and/or pins. These elements in relief may present a height thatis smaller than the height of the retaining elements, more particularlyless than 40% of the height of retaining elements, in particular lessthan 25% of the height of the retaining elements. Such elements inrelief can be advantageous in certain applications, e.g. in order todefine zones of distinct roughness or of different surface appearanceproviding advantages that may be practical and/or aesthetic.

When the substrate 200 and/or the support layer 330 is a nonwovenmaterial, the substrate 200 and/or the support 330 may be activatedprior to being secured to the intermediate layer, as mentioned above.

The term “plastics material” is used to mean a thermoplastic material,more particularly a polyolefin material based on a homopolymer or acopolymer.

By way of example, a plastics material from the following list: linearlow density polyethylene (LLDPE), low density polyethylene (LDPE),metallocene polyethylene (m-PE), high-density polyethylene (HDPE),ethylene vinyl acetate (EVA), and polypropylene (PP), having a molecularweight distribution that is monomodal or multimodal (e.g. bimodal), inparticular a composition comprising LLDPE and a plastomer, in particulara plastomer based on polyethylene. It is also possible to use polyimide(PA), polylactic acid (PLA), polyhydroxyalkanoates (PHA), polyvinylalcohols (PVOH), polybutadiene styrene (PBS).

The term “elastic material” is used to mean a material suitable forbeing stretched under the effect of a stretching force exerted in thelateral direction and then for returning substantially to its initialshape and dimensions after said stretching force has been released. Byway of example it may be a material that conserves residual deformationor remanence after elongation and release (where such residualdeformation is also referred to as “permanent set” or “set”) that isless than 30%, or indeed less than 20%, e.g. less than 5%, of itsinitial dimension (prior to elongation) after being lengthened by 100%of its initial dimension, and at ambient temperature (23° C.). Set canbe measured as described in patent application EP 1 783 257, the contentof which is incorporated by reference, and in particular the paragraphs[0056] to [0062] of the publication EP 1 783 257 A1 which describe indetail an example of measuring set.

As examples of elastic materials, mention may be made of:styrene/isoprene copolymers (SI), styrene/isoprene/styrene (SIS),styrene/butadiene/styrene (SBS), styrene-ethylene/butylene-styrene(SEBS), styrene-ethylene/propylene-styrene (SEPS), or styrene isoprenebutadiene (SIBS). It is also possible to take account of mixtures ofthese elastomers with one another or with non-elastomers that modifycertain characteristics other than elasticity. For example, up to 50% byweight, but preferably less than 30% by weight of polymer may be addedin order to modify certain characteristics of the base materials(elasticity, high-temperature behavior, processability, resistance toultraviolet (UV) radiation, . . . ), polyvinyl styrenes, polystyrenes orpoly a-methyl styrenes, epoxy polyesters, polyolefins, e.g.polyethylenes or certain ethylene/vinyl acetates, preferably those ofhigh molecular weight.

In particular, the elastic material may be a styrene-isoprene-styrene,e.g. available from the supplier Kraton Polymers, under the name KRATOND (registered trademark), or from the supplier DEXCO POLYMERS LP underthe name VECTOR SBC 4211 (registered trademark). It is also possible touse thermoplastic elastomer (TPE) materials in particular athermoplastic elastomer of polyurethane, in particular PELLETHANE(registered trademark) 2102-75A from the supplier The Dow ChemicalCompany. It is also possible to use a styrene-butadiene-styrene, inparticular KRATON D-2122 (registered trademark) from the supplier KratonPolymers, or VECTOR SBC 4461 (registered trademark) from the supplierDexco Polymers LP. It is also possible to use astyrene-ethylene/butylene, in particular KRATON G-2832 (registeredtrademark) from the supplier Kraton Polymers, or a sequencedstyrene-ethylene-butylene-styrene copolymer (SEBS), in particular KRATON(registered trademark) G2703. It is also possible to use a copolymer ofisooctyl acrylate and of acrylic acid with a monomer ratio of 90/10. Itis also possible to use a sequenced polyimide polyester copolymer PEBAX(registered trademark) 2533 from the supplier Arkema.

Other possible materials are polyolefins polymers, mainly copolymers ofethylene and/or propylene having the characteristics of elastomers, inparticular obtained by metallocene catalysis, such as VISTAMAXX VM-1120(registered trademark), available from the supplier Exxon Mobil Chemicalor indeed rubber-filled polymers such as for example Santoprene filledwith EPDM.

It is also possible to use materials to enhance bonding between theplastics material and the elastic material. In a variant embodiment, itis possible to envisage that each of the cavities in the molding stripincludes a stem that extends between the top face and the bottom face ofthe molding strip, from one of its faces to the other.

Various systems and methods compatible with the present disclosure aredescribed in patent applications FR 16 53866, FR 16 53870, FR 16 53872,FR 16 53873, FR 16 53888, FR 16 53894, and FR 16 53897, which areincorporated in full by reference in this description.

1. A method of forming a retaining device with hooks, wherein: a moldingstrip is provided that presents an inside face and an outside face, andthat has a plurality of cavities, each cavity defining a stem extendingfrom the outside face towards the inside face and including an endforming a head that extends from the stem towards the inside face of themolding strip; the molding strip is positioned on rotary drive means,the inside face of the molding strip being arranged to bear against thedrive means; molding material is dispensed against the outside face ofthe molding strip via material dispenser means arranged facing themolding strip in such a manner as to define a gap between the materialdispenser means and the molding strip, the step of dispensing moldingmaterial being performed in such a manner as to fill said gap and thecavities with molding material so as to form a tape comprising a base ofthickness that is defined by the gap, and first preforms projecting fromsaid base, each comprising a stem and a head, the first preforms beingformed by the plastics material in the cavities of the molding strip;and the tape is unmolded in such a manner as to deform the firstpreforms plastically so as to obtain second preforms of shape that isdifferent from the first preforms.
 2. A method according to claim 1,wherein after the unmolding step, a forming step is performed duringwhich the unmolded tape is inserted into a forming device so as tomodify the shape of the heads of the second preforms by forming.
 3. Amethod according to claim 2, wherein the forming device comprises atleast two rotary elements, each of said rotary elements having a speedthat is different from the drive speed of the tape.
 4. A methodaccording to claim 2, wherein the molding material is polypropylene, andwherein during the forming step, at least one forming element of theforming device is maintained at a temperature lying in the range 75° C.to 165° C.
 5. A method according to claim 1, wherein the step ofunmolding the tape leads to a change in the height of the head and/or ofthe stem, and/or to a change in the width of the head and/or of thestem.
 6. A method according to claim 2, wherein the forming devicecomprises an element at ambient temperature, and at least one element ata temperature that lies strictly between the heat deflection temperatureand the melting temperature of the molding material.
 7. A methodaccording to claim 2, wherein the forming step produces at least onedeformation of a portion of the head of each of the second preforms,said at least one deformation tending, for each preform, to deform oneof the ends of the head of the preform so as to form a rib on the topface of the head of the preform.
 8. A method according to claim 1,wherein, during the step of dispensing the molding material, the gapbetween the material dispenser means and the molding strip lies in therange 10 μm to 700 μm.
 9. A method according to claim 8, wherein themolding material is polypropylene, and the step of dispensing themolding material is performed at a pressure lying in the range 30 bar to50 bar, and at a temperature lying in the range 150° C. to 300° C.
 10. Amethod according to claim 9, wherein the molding strip is driven at atravel speed lying in the range 1 m/min to 500 m/min.
 11. A methodaccording to claim 1, wherein the unmolding step is performed while thebase of the tape is at a temperature lower than the melting temperatureof the molding material, or lower than the heat deflection temperatureof the molding material.
 12. A method according to claim 1, wherein thestep of dispensing the molding material is performed so as to form atape extending in a longitudinal direction and comprising a basepresenting two edges in the longitudinal direction, each of the edgespresenting highs and lows, wherein the maximum offset between the highsand the lows in a direction transverse to the longitudinal direction isless than 1 mm over a length in the longitudinal direction correspondingto three consecutive highs.
 13. A method according to claim 1, whereinprior to the unmolding step, a layer of nonwoven material is appliedagainst the bottom face of the base before said bottom face of the basehas solidified so as to cause portions of the fibers and/or filaments ofthe layer of nonwoven material to penetrate into the base, at least inpart.
 14. A method according to claim 13, wherein during the step ofapplying the layer of nonwoven material against the bottom face of thebase, the layer of nonwoven material is at ambient temperature, and thetemperature of the base is the result only of the step of forming thetape.
 15. A method according to claim 13, wherein during the step ofapplying the layer of nonwoven material against the bottom face of thebase, the bottom face of the base is at a temperature lower than itsmelting temperature.
 16. Apparatus for performing a method according toclaim 1, comprising: a molding device, comprising a molding stripmounted on rotary drive means, the molding strip having an inside faceand an outside face, the inside face being mounted to bear against therotary drive means, the molding strip having a plurality of cavities,each cavity defining a stem extending from the outside face towards theinside face, and including an end forming a head that extends from thestem towards the inside face of the molding strip; material dispensermeans arranged facing the molding device, and configured in such amanner as to dispense molding material at a point of the molding stripso as to form a tape of preforms having a base of thickness defined by agap between the material dispenser means and the molding strip, andfirst preforms, each comprising a stem and a head projecting from saidbase; unmolding means configured to unmold the tape of preforms formedin the molding strip; and the molding strip and the unmolding meansbeing configured so that unmolding the tape of preforms leads to thefirst preforms being deformed plastically in such a manner as to formsecond preforms of a shape that is different from the first preforms.17. Apparatus according to claim 16, further comprising a forming deviceconfigured to modify the heads of the preforms by forming.
 18. Apparatusaccording to claim 16, further comprising drive means for driving alayer of nonwoven material and adapted to press a nonwoven materialagainst the bottom face of the base of the tape of retaining elementsdownstream from the material dispenser means.